1. Field of the Invention
The present invention relates to a continuous process for purifying an off-gas composed of CO.sub.2 +HCl+COCl.sub.2.
This off-gas mixture is produced, for example, in the preparation of carbonyl chlorides.
Carbonyl chlorides are prepared as shown by the following equation: ##STR1## where COCl.sub.2 is introduced in excess into the reaction, and N,N-dialkylformamide is used as catalyst.
2. Description of Related Art
The off-gas from the reaction is thus composed of CO.sub.2, HCl and unreacted COCl.sub.2.
In the prior art, the above off-gas mixture is scrubbed with water with added ammonia in scrubbers packed with active carbon. The recovery or disposal of the HCl resulting from this is complicated and therefore cost-intensive.